1.
AUbrzanje usljed gravitacije je 10 N/kg. Površina ribe koju pritiska voda iznad nje je 6 cm2Odredite silu vode iznad ribe koja djeluje na ribu.
Poznato:
Ubrzanje zbog gravitacije (g) = 10 N/kg
Surface area of fish (A) = 6 cm2 = 6 x 10-4 m2
gustoća of water = 1 gram/cm3 = 1 (10-3 kg) / 10-6 m3 = 103 kg / m3 = 1000 kg/m3
Height of water = 100 cm – 15 cm = 85 cm = 85 x 10-2 Metara
Traži se: Force of the water above fish that acts on fish
Rešenje:
Jednadžba pritisak:
P = F / A
F = P A
F = ρ g h A
F = (1000)(10)(85 x 10-2)(6 x 10-4 m2)
F = (104)(510 x 10-6)
F = 510 x 10-2
F = 5.1 Njutna
2. The normal pressure of blood is 80 mm hg to 120 mm hg. This value is equal to…
A. 80 Pascal to 120 Pascal
B. 800 Pascal to 1200 Pascal
C. 10256 Pascal to 17589 Pascal
D. 10526 Pascal to 15789 Pascal
Poznato:
The normal pressure of blood = 80 mm Hg – 120 mm Hg
Wanted: This value is equal to… Pascal
Rešenje:
The height of mercury in a barometer (above the surface of the sea) = 760 mm Hg
Pressure of air (above the surface of sea) = 1 atm = 1.0 x 105 paskal
1 mm Hg = ……. Pascal?
80 mm Hg = 80 x 131.58 Pascal = 10,526 Pascal
120 mm Hg = 120 x 131.58 Pascal = 15,789 Pascal
Tačan odgovor je D.
3. Above the surface of the sea, the height of mercury in a barometer is 760 mm. If at a place, the height of mercury in a barometer is 700 mm. Determine the pressure of air at that place.
Poznato:
The height of mercury in a barometer (above the surface of the sea) = 760 mm Hg
Pressure of air (above the surface of sea) = 1 atm = 1,013 x 105 paskal
Wanted: Determine the pressure of air if the height of mercury is 700 mm
Rešenje:
760 mm Hg = 1.013 x 105 paskal
700 mm Hg = ……… Pascal?
